1. Field of the Invention
The present invention relates to a communication terminal and a communication system, and, more particularly, to a pager capable of displaying an image like a portrait and a paging system for the pager.
2. Description of the Related Art
Known systems for transmitting information such as numerals and characters include a paging system, a teleterminal system and a digital portable telephone system. Of those systems, the paging system is very popular as personal communication means as well as business communication means because portable terminals (pagers) are compact and light and their services charges are inexpensive although the paging system is a one-way communication system.
Pagers with a display function include an NP pager (Numeric Pager) type capable of displaying numerical information and an IP page (Information Pager) type capable of displaying character information. A telephone, a personal computer and the like are used as means for calling a pager and inputting a message to be displayed. There are companies which process transmission information, operation service companies and the like.
Information prepared by a telephone, a personal computer or the like is transmitted via a public telephone line to a pager service company. The pager service company converts the received information to a radiowave of a predetermined signal system, e.g., the POCSAG system, and transmits the radiowave.
The NP type pager informs the user of a ringing (calling) by some sound and displays a sequence of numbers included in the received signal. While an IP type pager informs the user of a call by some sound and displays character information included in the received signal. With the use of the NP type or IP type page, a message formed by a sequence of numbers or character information can be displayed on the pager and can thus be transmitted to the pager owner.
In a paging system using pagers which can display character information and a sequence of numerals, only one way of informing the users of the importance, urgency and the like of the received message is to change the ring back tone informing the user of a ringing. Therefore, the conventional pagers suffer poor expressions and have a difficulty in clearly informing the users of callers, the urgency or importance of a message, or the intentions or feeling of the callers.
This shortcoming is common to other types of communication terminals and communication systems which transmit information in the form of characters, numerals, symbols or the like.